The CLL says that "su'o" ("at-least-X") by default means "at-least-one". The "pa" is still part of the outer quantifier, so "su'o prenu" means "su'opa lo ro prenu" (at least one of all those which really are people).

Similarly, "su'e prenu" means "su'epa lo ro prenu", at most one of all those which really are people.